Five deep holes were drilled deep into the bedrock of Bragg Hill this week. One for our domestic drinking water, the others for geothermal heating and cooling. While not much to look at the surface, the science of drilling used here was sophisticated and was performed with precision. Ken Madron from K.L Madron Well Drilling performed the service.
Of interest are the four geothermal wells. Unlike the domestic water well, these holes were drilled dry to a depth of 330 feet. This depth and number of geothermal wells were calculated based on the specific energy requirements used by 60 Bragg Hill. Because our home was designed and built with extreme thermal efficiency, the added energy required to heat and cool the home will be quite modest. Geothermal systems Uses the earth’s constant 55 degree temperature as a conduit for heating and cooling. This drastically reduces the energy load on air conditioning and heating units. Because of this our heating and cooling units are much smaller than would otherwise be required for a home of our size.
Our geothermal system is designed with four closed-loop wells. Each well contains a sealed loop of pipe containing a special liquid designed to transfer heat from one substance to another. This liquid will be slowly cirulated from the HVAC equipment into the 330 foot well and looped back in to the equipment. In our case we’ll use both a water-to-water unit for our radient floors and a water-to-air unit for our air conditioning. The term “water” in the first part of the phrase represents the liquid cirulating in the geothermal wells. The long pipe loop is inserted in the well hole and then encased in a special silica based thermal grout designed to maximize the transfer of the earth’s stable temperature to and from the sealed liquid in the pipe.
It sounds very complicated, but it isn’t. What is complicated however, is the maze of pipes and valves that will consume our two mechanical rooms in the lower level. That will be detailed in another article.